The English composer Colin Matthews turned 50 this week, but there's no sign that his sense of adventure is abating. Composing, he says, is still a surprising business. "It's as though I go to my desk and find layers of stones lying there. I chisel away at them and see what kind of sculpture takes shape - I never really know what's going to emerge." Even the best-laid plans have a habit of taking on a life of their own, as happened with two works on a new DG disc: the teeming, vibrant Suns Dance (1985), for 10 instruments, and Broken Symmetry (1992), an elementally violent scherzo for large orchestra.
"They're full of complicated, almost machine-like musical processes, but after I'd written them, I discovered all kinds of things I'd never realised were there. There's one bar of silence in Suns Dance - the only point where nobody plays - and, would you believe it, it comes right at the point the classical theorists called the 'Golden Section' - the proportion which was thought to guarantee formal perfection. The same thing happens at the climax of Broken Symmetry. How did that happen?"
The first piece on the new DG disc is a reminder of how long Matthews has been pursuing his course of discovery. Fourth Sonata, for orchestra, was written in the years 1974-5. It sounds like a head-on confrontation with American minimalism: a modern European composer, schooled in Mahler, Schoenberg and the later Britten, takes on the populist John Adams and the recent, more romantic Steve Reich, and comes up with something utterly personal. But Adams was a student in 1975, and Reich was still in the earlier (and, for many, riper) phase that produced Drumming, a gloriously "primitive" celebration of rhythm and pure percussive timbre - the sugary harmonies and softer sounds of The Desert Music were still to come.
A recent performance of Fourth Sonata at America's Tanglewood Festival brought this home to Matthews, and, it seems, to other members of the audience. "It was fascinating to hear it in an American context, played by American musicians. It was as though the piece had come home. Some of the reviews said the same - here was this Englishman anticipating John Adams!"
But, unlike Adams and Reich, Matthews never fully embraced minimalism. "Well, there was one piano piece I wrote in the early Seventies that was fairly committed to minimalist principles - continuous pulsations, repetition, clear, tonal harmonies. But I cannibalised it for Fourth Sonata - that's where the ideas came to fruition."
What was it about minimalism that appealed to Matthews? "I think it was a way of getting myself out of a compositional rut. At the time, I couldn't see my way forward. Before then, I'd been writing some not very accomplished serialist pieces. Minimalism appealed because it was a new way of doing things, something that enabled me to take a right-angled turn and start again. That deflection was very valuable."
Still, even in Fourth Sonata, a major difference between Matthews and the new Americans emerges. Matthews's works have tended to be much darker in mood, often with violent tendencies. If there is a vision behind Broken Symmetry, for instance, it does seem to be a pessimistic one - the machine stops, or breaks apart: result, catastrophe. "I wouldn't say I'm a pessimist, more a realist. But when I compose, I haven't a clue why I've done things. When I'd written Broken Symmetry, I thought, 'What have I done?' It's tough stuff, I admit, but I never thought in terms of mood or message.
"I often think of Tchaikovsky, who said that he was happiest of all when he was writing his Fourth Symphony - music that's full of gloom and doom. My music does alarm me sometimes. I think, if really I am like that, I'm obviously repressing rather a lot... But I think the viciousness and darkness come out in a reaction against the mindless affirmation of minimalism. I feel like grabbing it with my teeth and shaking it about a bit."
It's hard to imagine a better introduction to Hidden Variables, the first work on another new all-Matthews disc, this time from Collins Classics. Antony Bye, writing in the Collins CD booklet, describes Hidden Variables as a "battle for the soul of modern music" - brash, mechanical exuberance versus acerbically protesting modernism. But there's humour too - plenty of it - which hints at a more pluralistic view: maybe the conflict between modernism and populism isn't a simple opposition of good and evil after all?
"I'm all for pluralism. The world of New Music may be small, but it's full of silly cliques, and it's got worse recently. You have the Hecklers on one side, the Complexity devotees on the other, both attacking the mainstream. But what is the mainstream? In global terms it doesn't mean an awful lot. The audience for new music has always been tiny, and so little survives. The move away from the vernacular in music is a problem - Schoenberg will always be difficult. But should we always be thinking in terms of large audiences?"
Matthews continues to do his bit for pluralism: as founder and executive producer of the contemporary music record label NMC, as administrator of the Holst Foundation and as a director of the Performing Right Society. "I do draw some encouragement from what's happened at NMC. We try to be as broadly based as possible - dense, prickly modernism and simplicity, James Dillon and Howard Skempton; and between those extremes there's so much variety - much more than most of the currently vocal opponents of contemporary music seem to think."
Matthews's own music can be surprisingly wide in its embrace: not just swinging from modernism to minimalism, but drawing in Mahlerian warmth and tenderness and the lush, exotic dreamscapes of the increasingly popular Szymanowski (the Polish composer's First Violin Concerto was a seminal influence). There are even occasional hints of old-fashioned humanism. "It is easier to write black music, and much harder to come out the other side, but I do feel the urge to try."
Perhaps the soon-to-be-completed orchestral triptych - linking Broken Symmetry, the orchestral work Memorial (featured on the new Collins disc) and an as-yet-unnamed choral work - will show how Matthews has "come out the other side" of his former black "realism"; a performance is planned for September, with the BBC Symphony Orchestra conducted by Andrew Davis.
Matthews has an even bolder plan: a comic opera. Bolder because, with the glowing exceptions of Britten's Albert Herring and A Midsummer Night's Dream, it's hard to think of a single lastingly successful operatic comedy written since the end of the Second World War. Matthews's Machines and Dreams, a kind of late 20th-century Toy Symphony (also on the Collins disc), shows that his musical sense of humour isn't always as barbed as in Hidden Variables. Still, this may be another of those projects that takes on a life of its own - one of those "stones" from which a completely unexpected musical sculpture emerges. "Perhaps, but for the moment I'm just delighted that, in spite of everything, those stones keep turning up."
n Broken Symmetry, Suns Dance, Fourth Sonata (London Sinfonietta / Knussen) on DG 447 067-2. Hidden Variables, Quatrain, Memorial, Machines & Dreams (LSO / Tilson Thomas) on Collins Classics 14702